Thermochemistry of SiO(OH) Vapor Species from Quantum Chemical Calculations.

The thermochemistry of the Si-O-H system has been extensively studied both experimentally and theoretically due to its importance in chemical processes, degradation of silica-protected materials in combustion, and geological processes. In this paper, we review past studies and use quantum mechanical methods to generate a new data set. Molecular geometries were generated with DFT using the B3LYP functional.

Modeling Singlet Oxygen-Induced Degradation Pathways Including Environmental Effects of 1,2-Dimethoxyethane in Li-O Batteries through Density Functional Theory.

We employ density functional theory (DFT) to examine reaction mechanisms involving singlet oxygen Δ (O) and 1,2-dimethoxyethane (DME) to probe potential parasitic reactions occurring in Li-O batteries. First, we investigate the attack of O on the ethylene group (-CH-CH-) to form HO and a C-C double bond in a single step. Second, we look at hydroperoxide formation that occurs via a two-step mechanism.

Quantum chemical and experimental thermodynamic studies of HfO(g).

Hafnium dioxide vaporizes primarily to HfO(g) in a reducing environment. The thermochemistry of HfO(g) is calculated from quantum methods and measured via Knudsen effusion mass spectrometry. For the computations, all-electron and relativistic effective core potential calculations are used.

Computational Chemistry Derivation of Cr, Mn, and La Hydroxide and Oxyhydroxide Thermodynamics.

Thermodynamic quantities are calculated for gaseous hydroxides and oxyhydroxides of Cr, Mn, and La. These would form due to water-vapor-containing environments reacting with Cr-forming alloys or oxide components of potential fuel cell interconnects or anode materials. Structures and vibrational modes for the expected hydroxides and oxyhydroxides are calculated with the B3LYP hybrid functional.

Reaction of Singlet Oxygen with the Ethylene Group: Implications for Electrolyte Stability in Li-Ion and Li-O Batteries.

Recent experimental and computational evidence indicates that singlet oxygen (O) attacks the ethylene group (-CH-CH-) in ethylene carbonate (EC) leading to degradation in Li-ion batteries employing EC as the electrolyte solvent [ , , 8828-8839]. Here, we employ computational quantum chemistry to explore this mechanism in detail for a large set of organic molecules. Benchmark calculations comparing density functional theory to the complete active space second-order perturbation theory and internally contracted multireference configuration interaction indicate that the M11 functional adequately captures trends in the transition-state energies for this mechanism.